Why does the Upgrade Advisor check for Unit Delay and Zero-Order Hold blocks for rate transition give an error ?

I am trying to run the Upgrade Advisor while transitioning from Matlab 2012a to 2014b. The check for Unit Delay and Zero-Order Hold blocks for rate transition gives me a failure with the following error: Error occurred during model compile. Invalid block diagram

I get this error even if my model does not contain any unit delay/zero-order hold blocks. Is this because I am running this advisor on a library model?